Sealed chamber to control the environmental condition of printer media

ABSTRACT

A tray for holding a media roll being fed to a paper path of a copier/printer including a plurality of wall defining a chamber, the chamber including: an open portion thereof for receiving the print media roll; a cover for opening and closing the open portion of the chamber, a first seal associated with the chamber and cover, for preventing air from exiting or entering when the cover closed, a sheet slot defined in one of the plurality of wall, for feeding print media therethrough to the paper path of the copier printer; and a second seal, associated with the sheet slot, for to preventing air from exiting or entering the chamber as roll media is fed.

[0001] This application is based on a Provisional Application No.60/315,415 filed Aug. 28, 2001.

[0002] This invention relates to a copier/printer employing a roll mediafeed apparatus and, more particularly, to a sealed chamber for holdingroll media for use with such an apparatus.

[0003] Copying relatively large size documents such as engineeringdrawings and the like normally requires that the copy, media material besupplied from a roll assembly. As a result, it is necessary that themedia material be cut to size from the roll being used, and for thispurpose, a cut media roll supply is desirable. Typically, a cut, mediaroll supply of the type referred to herein includes a roll support whichholds and permits the roll to be unwound as sheets are cut therefrom,and a sheet cutter such as a rotary cutter which cuts or severs thesheet material in two. Also conventional is a handling apparatus forunwinding the media material from the supply roll and advancing a lengthselected to the sheet cutter, and a machine control system forintegrating and synchronizing operation of the various components. It isalso desirable that the sheet cutter be able to cut, with the utmostreliability and accuracy, a wide range of media materials such as bond,vellum, film, tracing paper, and the like in addition to a wide range ofpaper weights. For example, prior art rotary bar type cutters asdisclosed in U.S. Pat. Nos. 4,058,037 and 3,879,123, both of whosecontents are hereby incorporated by reference.

[0004] However, major problems with roll media feeders include ensuringthat the roll media has not changed dimension while in machine whichresults in increase print curl of resultant copies and increases chancesof jamming. Printer media should be stored in an environment with arelative humidity of 35% to 55%. Humidity conditions outside of thisrange can cause poor quality printing and paper distortion. Mostprinters require external conditioning of the ambient environment(either humidification or dehumidification) to maintain the printingmedia at proper humidity conditions. Some printers incorporate heatingelements to raise the temperature of the air in the media chamber andreduce the relative humidity.

[0005] Accordingly, the present invention provides a tray for holding amedia roll being fed to a paper path of a copier/printer including aplurality of wall defining a chamber, said chamber including: an openportion thereof for receiving the print media roll; a cover for openingand closing said open portion of said chamber, a first seal associatedwith said chamber and cover, for preventing air from exiting or enteringwhen said cover closed, a sheet slot defined in one of said plurality ofwall, for feeding print media therethrough to the paper path of thecopier printer; and a second seal, associated with said sheet slot, forpreventing air from exiting or entering said chamber as roll media isfed.

[0006]FIG. 1 is an isometric view of a copier/printer which employs thedual use sensors of the present invention.

[0007]FIG. 2 is a partial, exploded, schematic side view of thecopier/printer of FIG. 1 showing the placement of the dual use sensors.

[0008]FIG. 3 Illustrates an isometric view of sealed media chamber ofthe present invention.

[0009] Referring now to the drawings in detail wherein like numbersrepresent like elements, in FIG. 1 a wide format copier/printer 10including a control panel 12 is shown which is especially adapted tocopy large documents. Documents to be copied are fed in from the frontof the machine, pass through an exposure zone and exit out of the backof the machine.

[0010]FIG. 2 shows a side internal view of the copier/printer machine10. Machine 10 includes an electrostatic drum 20 with xerographicstations arranged around its periphery, which carry out the operationalsteps of the copying process. These stations include charging station22, exposure station 24, developing station 26, transfer station 28 andfusing station 30. Documents fed along the platen 19 in the direction ofarrow 8 are imaged onto the surface of drum 20, at exposure station 24.The operations of the stations are conventional and are described, forexample, in U.S. Pat. Nos. 4,821,974; 4,996,556; and 5,040,777, whosecontents are incorporated herein by reference.

[0011] Copy media, which may be bond paper, vellum, or the like, is cutfrom the selected media roll assembly 14A, 14B or 14C and is fed by arespective feed roller pair 32A, 32B or 32C. The sheet to be cut isguided along a vertical path between baffle pairs into the sheet cuttingbar assembly 16 which includes a stationary blade 42 and a rotatingcutting bar 44 that includes a helical cutting blade. Cutter bar 44 isshown in the home position which is about 30 degrees of rotation awayfrom the cutting position and is driven by motor 60. Cutter assembly 16is of the type described, for example, in U.S. Pat. No. 4,058,037,referenced supra. Initiated by a cutter operation signal, bar 44 rotatesin the direction of the arrow with its blade moving against blade 42 tosheer a sheet 50 from the roll media with a straight cut.

[0012] The cut sheet is transported after registration by roller pair 51into baffle 52 and then into transfer station 28 where a developed imageis transferred onto the sheet. The cut sheet is then forwarded throughtransfer station 30 and out of the machine.

[0013] In order to cut machine cost, maintain control of the media andmonitor the media from initialization to the registration roll pair,three reflective media sensors (33A, 33B, and 33C) are employed in thepaper path leading to registration roll pair 51. The sensors areconfigured to provide a dual function. The first function of the sensorsis to initialize the media to a predetermined nominal position, forexample, if a new roll 14C of media is loaded into machine 10, the medialead edge is indexed into a nominal feed start position once theoperator loads the media feed edge into pinch roll pair 32C. That is,after the machine doors are closed, sensor 33C is adapted to sense thelead edge of the media. If the lead edge is not detected, the media isautomatically fed forward toward media sensor 33C by pinch roll pair 32Cuntil the lead edge is detected by sensor 33C, pinch roll pair 32C isreversed by a conventional media rewind drive (not shown) for a pre-settime interval with the media lead edge being placed in a predeterminednominal position as shown. If media sensor 33C initially detects thelead edge of the media after the operator loads the media into themachine, pinch roll pair 32C reverses until the media lead edge uncoversthe sensor and continues to rewind to the nominal position between pinchroll 32C and sensor 33C. The media initialization procedure is the samewhen loading media rolls 32B and 32A. A second function of sensors 33A,33B and 33C is to monitor progress of media through the machine'spredetermined paper path during each feed cycle. The sensors 33A, 33Band 33C monitor the lead edge of the media as it is fed vertically upthe media path until the lead edge of each cut sheet reachesregistration sensor 35. For example, when an operator selects media roll14C on control panel 12 and a copying cycle is initiated by themachine's conventional microprocessor controller, pinch roll pair 32C isenergized and the media begins to feed toward sensor 33C.

[0014] The media lead edge will be detected by sensor 33C within apredetermined window. Each of the three sensors 33A, 33B and 33C have apredetermined time window within which the media lead edge should bedetected as it progresses toward registration sensor 35. If any of thethree media sensors do not detect the media lead edge within thepredetermined time interval, a jam is indicated and the machine isstopped automatically for operator interaction.

[0015]FIG. 3 illustrates an isometric view of sealed media chamber ofthe present invention. Lid 110 is hinged along panel chamber 105 whichallows the operator to load media into chamber 200. The top 106 ofchamber 105 has a seal 112 which prevents air from entering or leavingchamber 105. During media loading, an operator lifts baffle 33 whichholds media secured during media feeding. Seal 117 is positioned onupstream from pinch roll pair 32C and prevents air from enter or leavingchamber 105. Seal 117 comprises a thin plastic sheet or blade whichurges the media against chamber 105. When copy cycle is ended with media14C the lead edge of the media is reversed downstream of seal 117.

[0016] Applicants have found that the sealed chamber helps producehigher quality prints over a wide range of environmental conditions. Inrecapitulation, there has been provided a passive system that willmaintain printing media at the proper humidity level regardless ofambient humidity conditions. A sealed enclosure prevents the media frombeing exposed to ambient humidity conditions, and creates a storageenvironment in which the humidity is in equilibrium with the media. Noactive humidity controls are necessary. The media is fed out of thesealed environment and exposed to ambient conditions only during theprint cycle.

[0017] The invention consists of an enclosure made from a suitablematerial such as plastic or sheet metal, with a removable cover thatallows access to the printer media. Gaskets and seals or a suitablesealer material such ‘Silicone RTV’ are used on all removable surfacesand where shafts, mechanisms or wires must pass through the enclosure.During printing the media exits the enclosure through a seal consistingof a very thin plastic sheet that does not impede the motion of themedia in the forward or reversible directions.

[0018] While the invention has been described with reference to thestructure disclosed, it is not intended that the invention be confinedto the details set forth, but it is intended to cover modifications orchanges as they come within the scope of the following claims.

What is claimed is:
 1. A tray for holding a media roll being fed to apaper path of a copier/printer, comprising: a plurality of wall defininga chamber, said chamber including: an open portion thereof for receivingthe print media roll; a cover for opening and closing said open portionof said chamber, a first seal associated with said chamber and cover,for preventing air from exiting or entering when said cover is closed, asheet slot defined in one of said plurality of wall, for feeding printmedia therethrough to the paper path of the copier printer; and a secondseal, associated with said sheet slot, for to preventing air fromexiting or entering said chamber as roll media is fed.
 2. The trayaccording to claim 1, further comprising a media feed roll for feedingroll media to the paper path of the copier printer.
 3. The trayaccording to claim 1, where said second seal comprises a thin bladebias.
 4. The tray according to claim 2, further comprising controlmeans, in communication with said media feed roll, for moving a leadingedge of said roll media to a position downstream of said second sealwhen said tray is disable.